On Fri, 11 Sep 2015, Greg Kroah-Hartman wrote: > 4.1-stable review patch. If anyone has any objections, please let me know. It turns out that this patch causes problems with the sr driver. A reversion and alternate solution have already been submitted to James Bottomley (http://marc.info/?l=linux-scsi&m=144185206825609&w=2). We ought to hold off putting it into the -stable kernels. Alan Stern > ------------------ > > From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> > > commit 49718f0fb8c9af192b33d8af3a2826db04025371 upstream. > > The routines in scsi_rpm.c assume that if a runtime-PM callback is > invoked for a SCSI device, it can only mean that the device's driver > has asked the block layer to handle the runtime power management (by > calling blk_pm_runtime_init(), which among other things sets q->dev). > > However, this assumption turns out to be wrong for things like the ses > driver. Normally ses devices are not allowed to do runtime PM, but > userspace can override this setting. If this happens, the kernel gets > a NULL pointer dereference when blk_post_runtime_resume() tries to use > the uninitialized q->dev pointer. > > This patch fixes the problem by calling the block layer's runtime-PM > routines only if the device's driver really does have a runtime-PM > callback routine. Since ses doesn't define any such callbacks, the > crash won't occur. > > This fixes Bugzilla #101371. > > Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> > Reported-by: Stanisław Pitucha <viraptor@xxxxxxxxx> > Reported-by: Ilan Cohen <ilanco@xxxxxxxxx> > Tested-by: Ilan Cohen <ilanco@xxxxxxxxx> > Reviewed-by: Johannes Thumshirn <jthumshirn@xxxxxxx> > Signed-off-by: James Bottomley <JBottomley@xxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html